Field of the Invention
The invention relates to a woven-fabric belt which is suitable for employment in a machine producing and/or processing a fibrous web, in particular a paper, cardboard, tissue or non-woven machine.
Woven-fabric belts of the generic type comprise longitudinal threads which are interwoven with cross threads, while configuring thread intersection points. Such woven-fabric belts are typically manufactured in a flat weave and have an upper side and a lower side opposite thereto. In the intended use of such woven-fabric tapes in the machine, the longitudinal threads run in the MD direction, and the cross threads run in the CMD direction of the machine. Furthermore, the upper side points toward the fibrous web, and the lower side toward the machine. For employment in a machine producing and/or processing a fibrous web such woven-fabric belts which are originally produced in a flat shape are rendered endless on a woven-fabric seam region such that said woven-fabric belts are able to be operated as endless belts in the machine. Such a woven-fabric seam region may be provided by longitudinal threads which in the region of the longitudinal thread end portions thereof are woven in reverse so as to configure seam loops, for example. Such a woven-fabric seam region may also be formed by longitudinal thread end portions of longitudinal threads which are each gathered in pairs and which, while configuring a woven seam fabric having cross threads which often is identical to the flat-woven fabric portion are collectively interwoven with cross threads, often in portions along a common weaving path.
The tensile strength of the seam in the case of woven-fabric seam regions formed by seam loops as well as in those formed by the woven seam fabric depends inter alia on the number of cross threads with which the longitudinal thread end portions are interwoven during reverse weaving, or on the number of cross threads with which the gathered longitudinal thread end portions are collectively interwoven so as to follow a common weaving path. Here, the strength of the seam increases with the number of cross threads with which the longitudinal thread end portions are interwoven. However, physical properties such as, for example, the permeability and thickness of the woven-fabric belt, in the woven-fabric seam region are influenced by reverse weaving or by the common weaving path, respectively, such that these physical properties in the woven-fabric seam region vary from one location to another and are dissimilar to the remaining part of the woven-fabric belt.
In order for high tensile strength to be achieved, on the one hand, and for there to be no excessive variation in permeability and/or thickness, for example, on the other hand, it is proposed in the prior art that the longitudinal threads in the region of the longitudinal thread end portions thereof are connected in a materially integral manner to cross threads at least at some thread intersection points.
For example, in this way it is known from U.S. Pat. No. 8,062,480 and from EP1749924 for the longitudinal threads and cross threads to be connected in a materially integral manner at the thread intersection points by welding, using the influence of laser radiation.
However, it has now been demonstrated that the materially integral connection, for example the welded connection, between the longitudinal threads and cross threads at the thread intersection points is often inadequately durable. As has been demonstrated in research by the applicant, this issue arises in particular in the case of woven-fabric belts having an open and/or single-layer weaving structure. In order to produce a durable woven-fabric seam it has therefore been proposed that entire regions of the woven-fabric seam portion are connected in a materially integral manner, this in turn leading to undesirable rigidity of the woven-fabric belt in the longitudinal direction thereof.